The present invention relates to an apparatus and method for atomization of chilled or heated fluid, projection of droplets, and formation of a fluid film in a chamber with large surface area for heat exchange in the application of refrigeration, air conditioning, and heating of room, space, structure or dwelling.
Heat exchanger technology has long existed. Prior art for heat exchanger in application of refrigeration, air conditioning, commonly referred to as evaporator involves rapid expansion of compressed liquid refrigerant converting to gas inside a small diameter metal tube fitted with heat conductive fins. Heat is absorbed while ambient air is blown over this assembly by use of a motorized blower. For heating, the air is commonly heated by flame or by an electrical resistive heater. In some cases hot fluid is circulated inside a similar device as the evaporator described. Various configurations of this basic heat exchanger are exemplified by U.S. Pat. Nos. 6,192,976; 6,035,927; 6,182,743; 6,178,766; 6,173,763, and 6,167,950. Disadvantages of this type of heat exchanger are many. Small diameter tubing, even long in length, does not possess large surface area for heat transfer. Narrow thin fins, approximately on the order of 2.5 to 5 centimeters (1 to 2 inches) in width and 0.25 millimeter (0.01 inch) in thickness as commonly used, attaching edgewise to the tubing, limit heat transfer capacity. Heat conduction must also travel a distance from the fins to reach the tubing. Air contact time with the evaporator heat exchanger assembly is necessarily brief due to the limited width of fins and high velocity of air travelling over the evaporator, contributing to low heat energy transfer. Air molecules in immediate direct contact with cold or hot surfaces only perform heat exchange. Air is a poor heat conductor; molecule vibration caused by heat is not easily transmitted to adjacent molecules due to large distances separating them. Such inefficiency leads to requirement of large capacity refrigeration and heating units to provide a large temperature differential between the evaporator and ambient air at a sacrifice of energy consumption.
Prior efforts to increase surface area for heat exchange, particularly, in the application of cooling fluid, between fluid and fluid employing small corrugated tubing, have been exemplified by U.S. Pat. Nos. 6,119,769 and 4,995,454. However, such modified configurations are far from adequate for efficient heat exchange between fluid and air in the application of air conditioning and heating.
In a central air conditioning and heating system for a structure or dwelling, a large centrifugal blower generating air flow with high static pressure is needed to propel air through the heat exchanger or evaporator and furnace into a system of large ducts for distribution into various rooms and spaces through open grills. It has been verified by scientific studies that energy loss for a ducting system is greater than 20 percent of the total consumed by a central air conditioning and heating system. This energy deficit is primarily caused by heat gained or lost while chilled or heated air travels through the ducts even insulated according to recommended common practice. Significant air velocity is also diminished due to resistance from friction while air is in contact with large duct wall surface and confronting turns of the ducts necessary for reaching final destinations. A large centrifugal blower for a central air conditioning and heating system for an average size dwelling consumes kilowatts of electric power per hour.
One disadvantage of the above described ducting system is the requirement of multiple size ducts to balance air flow and temperature in various locations in a structure or dwelling dependent upon sizes, lengths, shapes, and turns of ducts. Proper balance of temperatures in all locations within a structure or dwelling is seldom achievable with such a method.
Baffles or shutters, preset or motorized, have been placed inside air ducts in larger or commercial buildings to regulate amount of air flow into a room or area in an effort to provide acceptable air flow and temperature regulation in air conditioning. Such efforts are energy wasting and far from satisfactory in delivering the right amount of conditioned air.
Another disadvantage of the above-described ducting system is that temperature of specific room or space within a structure or dwelling cannot be individually or incrementally controlled in an easy manner. A grill with louver adjusting mechanism located in a room or space has to be manually moved; therefore fine adjustment of temperature is not possible.
Another prior art of heating a structure or dwelling involves heating a large amount of fluid, generally water, with a large capacity water heater and conveying the heated fluid to various locations of a structure through a system of pipes. Once reaching a particular location, the pipe is arranged in a back and forth fashion and mounted under the floor, above the ceiling, or behind a wall as a heat exchanger radiating heat into a room or space. Such a heating system is commonly termed a “hydronic” heating system. One disadvantage of such a heating system is that a separate system is required for cooling. Another disadvantage is that a large amount of fluid is needed to be continuously heated thus requiring a large capacity heater with attending large energy consumption. Generally, temperature control in various locations is not available or possible. Furthermore, the structural element in which the “heat exchanger” is enclosed must first be heated before heat can radiate into a room or space. Occupants within feel the increase in temperature with significant delay. A warm building also radiates heat to cold outside environment wasting energy.
In view of the foregoing, it would be desirable to provide a more efficient heat exchanger and its integration into a functional system for refrigeration or air conditioning and heating purposes without all the above mentioned deficiencies.
The present invention provides a modular apparatus that continuously atomizes a small quantity of chilled or heated fluid into a large number of small droplets and projects the droplets onto a large surface area to form a fluid film for heat transfer. Atomization and projection is accomplished by centrifugal force generated by a rapidly spinning slotted and screen cylinder. Rotating cylinders with perforations and cylindrical screens have been described in U.S. Pat. Nos. 4,609,145 and 4,659,013. These various modes of atomization, primarily provided for agricultural spraying, possess shortcomings that render them unsuitable for application in this invention. They suffer the inability to uniformly generate droplets along the entire cylinder length or sustain the cylindrical shape for uniform droplet atomization under high rotating speed or centrifugal force.
Earlier attempts in generating droplets along the long axis of a rotating device by centrifugal force are also exemplified in U.S. Pat. Nos. 1,022,956 and 3,168,596. Unfortunately these prior arts generate narrow bands of droplets with large separation between bands; therefore they are unsuitable in an application requiring uniform and even droplet distribution.
The surface on which the fluid film is formed is the inner surface of a closed pleated corrugated chamber composed of thin gage heat conductive material for promotion of rapid and efficient heat transfer. Ambient air, provided by a blower, circulating on the outside of this chamber, has long contact time with the chamber surface and large surface area for greater amount of heat energy transfer.
Heat exchanger modules of this invention are intended to be located in rooms or spaces where air conditioning or heating is needed. A central fluid reservoir is employed for chilling and heating fluid to be atomized by the heat exchanger. Small bore tubes are used to convey pre-chilled or preheated fluid to a heat exchanger and return for re-chill and reheat, eliminating the need for large air ducts as in conventional practice. Small tubes are also more economical as well as much easier to provide complete insulation to maintain the heat-energy-state of the fluid in transit. By providing a blower in the heat exchanger module at site where the module is installed has many advantages. One such advantage is the circulating air to be cooled or heated in the immediate vicinity of the module. There is no need for a large central blower that consumes a large amount of energy. The temperature in a given room or space can be cooled or heated quickly without the problem of heat conduction of air over a long distance in returning to the central blower to be cooled or reheated again. An added benefit of this invention is the ability to control temperature where it is needed and to what extent in individual room or space. The heat exchanger module or modules in area or areas without human occupation within a structure or dwelling can be shut off for further savings on energy use.
The present invention of heat exchange module is equipped with a motorized variable valve for changing the rate of fluid being processed. Since the large heat transfer surface is so efficient, an increase of fluid entering the exchanger increases the heat transfer rate as well. The heat exchange rate of any given moment can be calculated by input fluid temperature, rate of fluid being processed, and the outbound fluid temperature from an integrated exiting processed fluid temperature sensor. This arrangement provides the heat exchanger's unique ability to actively respond to changing heat leakage (heat load) from amount of heat transfer by increasing or decreasing fluid input to be processed by the heat exchanger. After noting the heat transfer amount information at any given moment we can program an increase heat transfer rate to utilize available evaporator cooling or heater's heating capacity optimally for purpose of energy savings. It should be noted that all traditional air conditioners are passive with heat exchange rates affected by environment conditions from moment to moment resulting in greater waste of energy. This invention is differentiated from tradition air conditioners by being able to actively change heat transfer rate based on information gleaned from temperature sensors and control of motorized variable fluid valve (fluid processed rate).
A small air conditioner of this invention with a single heat exchanger module operating with a thermostat control can be employed as an instrument to measure a room's heat leakage (heat load) which utilizes the major portion of an air conditioner's capacity to counter. By keeping a room's temperature constant, the heat absorption or distribution rate is essentially the heat leakage rate which has not been able to measure previously.